Intellectual Property Office

Non-Confidential Disclosures

"Synthesis of Nano-sized Alpha-Alumina (alpha-Al203)"

PSU Inv. Disc. No 2911

Field of the Invention:

alpha- Al203 nanoparticles (1-100 nm) with controlled shape and size have applications as materials for use in the electronic, catalytic, automotive, cosmetic, pharmaceutical and biomaterials industries.

Inventors:

James H. Adair and Rajneesh Kumar

Invention status:

The invention has been reduced to practice. Samples are available for evaluation.

Background:

The subject invention builds upon U.S. Patent No. 5,759,213, which is entitled “Method for Controlling the Size and Morphology of Alpha-Alumina Particles”. The subject invention provides methods to produce nanosized -Al203 with sizes less than 100 nm under glycothermal conditions and to produce phase pure nanosized -Al203, which can be prepared as low as 235oC. Seed particle concentration, seed size and precursor pre-treatment are modified to achieve the desired nanosized alpha-alumina particles. The powders obtained were characterized for phase by Scintag X-ray diffractometer (XRD) and specific surface area by Gemini 2370 BET. The primary particle sizes were determined as equivalent spherical diameter (ESD) via the powder specific surface area (SSA) obtained by BET. Selected samples were observed for verification of particle size by Hitachi S-3500N scanning electron microscopy (SEM) and JEOL 2010F high-resolution transmission electron microscopy (HRTEM). Experimental results showed primary particle ESD from 95nm down to 40nm. In one experiment, TEM micrographs of the Al203 particles indicate that the particles have platelet morphology with face diameter between 20 nm to 60 nm and an aspect ratio of 2 to 5.

Invention description:

Because of its superior physical and chemical properties, Al203 is one of the most widely used ceramic material found in varied applications, including as abrasives, absorbents, catalytic support, human implants, diagnostic instruments and media for drug delivery. Sub-micron particles with polyhedral morphology can pack up to seventy percent (70%) theoretical density in the green state. This high packing density facilitates porosity reduction in sintered ceramic bodies and reduces temperature and time for sintering. Particles with platelet morphology can be arranged via self-assembly methods into single or multi-layers to close to 100% of theoretical density. Potentially, these could produce thin ceramic coatings with an array of interesting and useful anisotropic mechanical, optical and rheological properties. Other novel applications are anticipated.

Contact:

Mr. Matthew Smith
Sr. Technology Licensing Officer
Intellectual Property Office
113 Technology Center
The Pennsylvania State Univ.
University Park, PA 16802-7000
Phone: (814) 863-1122
Fax: (814) 865-3591
E-mail: mds126@psu.edu